For those who aren’t familiar, fake reviews arise when researchers associated with the paper in question (most often authors) create email addresses for reviewers, enabling them to write their own positive reviews.

The article — released September 23 by the Postgraduate Medical Journal — found the vast majority of papers were retracted from journals with impact factors below 5, and most included co-authors based in China.

As described in the paper, “Characteristics of retractions related to faked peer reviews: an overview,” the authors searched Retraction Watch as well as various databases such as PubMed and Google Scholar, along with other media reports, and found 250 retractions for fake peer review. (Since the authors concluded their analysis, the number of retractions due to faked reviews has continued to pile up; our latest tally is now 324.)